Haptomerus, Faust, 1889

Borovec, Roman & Nakládal, Oto, 2019, Haptomerus maculosus, a new species of the tribe Myorhinini from Zambia (Coleoptera: Curculionidae: Entiminae), Zootaxa 4563 (2), pp. 387-395 : 393

Relationships of Haptomerus

The relationships of Haptomerus from the Afrotropical region and from southern Europe have not been addressed, it being assumed that only one genus existed (e.g. Marshall 1908, Osella et al. 1998); however, Oberprieler (1995) has stated that “African species of Haptomerus are not congeneric with those of Europe”, and “the African members of Haptomerus differ from the Palearctic ones in possessing a rostral groove and are thus presumably derived from a different ancestor, presumably an African member of Peritelini “. Evaluation of the transverse groove separating the rostrum from the remaining part of the head is difficult in the view of the fact that the eyes are dorsally almost contiguous along their inner margins and the space between the epifrons and eyes is thus only extremely short. A transverse sulcus is not clearly visible in Haptomerus as in similar Afrotropical genera having a clear sulcus, such as Nastomma Marshall, 1908 or Ephimerostylus Faust, 1895 . In several species the sulcus is more visible, as for example in H. limis , or in some species almost invisible, as in H. brevitarsis . The only species with a wide vertex, H. aeneus , where evaluation of this character is clear, clearly lacks this sulcus. In assessment of other characters, Afrotropical Haptomerus are similar to European species in the very slender space between antennal insertions, rostrum laterally denuded of scales, slender mandibles, dorsal border of scrobe coalescent with dorsal border of rostrum in lateral view and reaching ventral border of eye, eyes very dorsally placed, nearly contiguous, first tarsal segment enlarged, abdominal ventrites with ventrite 2 slightly longer than ventrite 3 or 4 with suture between ventrite 1 and 2 straight, metaventral process narrower than transverse diameter of metacoxa, female sternite VIII with plate narrowly subtriangular with membranous posterior margin and ovipositor with short apical styli. All these characters make both Mediterranean and Afrotropical Haptomerus related. Contrary to these synapomorphies, at least H. aeneus differs by a wide vertex, a wide epifrons mainly due to space between antennal insertions and eyes completely placed in the elongated part of the head. The elongation of the head is evident to a different degree among all Haptomerus species. In H. limis and H. maculosus sp. n. almost the entire eye portion of the head is narrowed and elongate, while in H. aeneus the entire eye portion including the portion behind the eyes is elongate, so the head and rostrum together form a cylindrical tube and only the short posterior part of head enlarged. While Haptomerus is easily possible to separate from the similar genus Apsis Germar, 1820 by the edentate femora, suture between ventrites 1 and 2 straight and ovipositor with styli ( Apsis has all femora distinctly dentate, suture between ventrites 1 and 2 conspicuously sinuate and ovipositor lacking styli), its position with respect to the more recently described Parhaptomerus Osella & Lodos, 1979 is still unclear. Parhaptomerus was described based only on several characters such as punctation of striae, vaulting of elytral interstriae or ratio between tarsal segments 1 and 3, which differs also among all Haptomerus species. The only two characters which could be used to distinguish the genera are the suture between ventrite 1 and 2 slightly sinuate in Parhaptomerus (straight in Haptomerus ) and eyes placed on narrow, elongate part of head (but this character varies in Haptomerus ). Additional material of H. aeneus or species related to it can help to resolve what species belong in Haptomerus , and also its relationship to Parhaptomerus , as well as the status of the Afrotropical and European species.